FA High
Your boiler has detected that the water is flowing in the wrong direction through the pipes or that the temperature sensors have been installed on the wrong pipes.
Technical description: Flow return reversed
Typical repair cost: £100-250 (including labour)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Protect yourself from future repair bills
A boiler cover plan would cover faults like FA — no call-out fees, no surprises.
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Parts commonly replaced
- Flow thermistor
- Return thermistor
- Pump
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